Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuroscience > Lecture 2 - Neuroscience Methods 2 > Flashcards

Lecture 2 - Neuroscience Methods 2 Flashcards

1
Q

What is the purpose of neuroscience techniques

A

Study relationship between brain and behaviour
Idea: spatial resolution cellular temporal resolution ms
Whole brain studied simultaneously = so much data difficult analyse
Non invasive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the spatial and temporal resolution for fmri

A

Spatial resolution excellent

Temporal resolution not as good as electrophysiological methods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an example of structural imaging

A

MRI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the goals of structural imaging

A

Study anatomy
Identify abnormalities
Follow development
Show plasticity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the structural imaging methods of interest to Biological psychology

A

Computed tomography CT scans
MRI - Sir Peter Mansfield

Rely on contrast between tissue types white matter vs gray matter vs cerebrospinal fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Example of studying juggling in structural MRI

A

Baseline scan
Then juggling boys practice daily until reach certain skill level
After 3 months scanned again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Example of studying juggling in structural MRI results

A

Scan increase grey matter in occipital region

After 3 fourth months told not to practice increase gray matter reversed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the study of juggling in structural MRI tell us

A

Brain plasticity after motor learning

Not be confused with fMRI

Correspond area hMT/V5 visual motion area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Outline the extrastriate visual areas

A

Process input from geniculostriate system

V5 = dorsal pathway = vision
E.g. visual coordination grasping

Supported brain structures dorsal pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How to generate structural MR contrast

A

Core: magnet generating strong EM field = external static magnetic field. Throughout and around scanner
Outsider scanner protons soft tissues all oriented at random. Undergo spinning movement in random order
Axis oriented vertical axis field. Not random
Protons spin axis generate own MF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do protons spin axis to generate their own MF in generating structural MR contrast

A

Spin axis not completely vertical rotates about vertical axis
Precessional motion
More protons aligned parallel external (longitudinal) MF
Lower energy than antiparallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is 1 cell represented in structural MR contract

A

One cell represented by magnetic vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are important components in generating structural MR contrast

A

Radio frequency coils

Scanner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Outline the net magnetisation vector

A

Magnetisation changes in response to radio frequency pulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Outline use of compass and a magnet in structural MR contrast generation

A

Compass contained surrounding fluid
Beginning points north with earths magnetic field
Magnet applied compass point east
Remove magnet and needle returns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Apply findings of use of compass and a magnet to structural MR contrast generation

A

Protons in bod aligned external magnetic field = net magnetisation
Radio frequency pulse applied
Net magnetisation perpendicular external magnetic field
0% inner magnetic field line with net magnetisation vector
Radio frequency pulse removed net magnetisation vector returns to original state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is net magnetisation vector

A

Protons body aligned with external magnetic field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is MR signal measured in MR contrast generation

A

Radio frequency pulse removed net magnetisation vector returns original state
Net magnetisation direction external magnetic field recovers 100% pre radio frequency value
MR signal measured during recovery = readout

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the MR contrast generation draw on to produce signal

A

Sequences RF pulses and readout = MR protocol

Protons different tissue types gray vs white require different time realign = basis of MR contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens when you increase vertical component in MR contrast

A

Increase magnetisation
Protons aligned parallel with external magnetic field
That is parallel with external magnetic field
Increase longitudinal magnetisation
Spin lattice relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Outline structure specific time courses of spin lattice relaxation

A

Brain tissue faster relaxation than ventricles CSF T1 signal
Signal brain stronger
MR contrast tissue specific
Radio frequency coil what measures T1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What creates the resulting image in specific time courses of spin lattice relaxation

A

Combination specific radio frequency pulse

Specific readout time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the order of contrasts in specific time courses of spin lattice relaxation

A

T1 white matter > T1 gray > T1 CSF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Outline the effects of modifying radio frequency pulses and read out times on MR properties

A

T2 signal white matter < gray matter < CSF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the goal of a functional MRI

A

Identify brain areas support sensory and cognitive processes
Derive models brain function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does an fMRI measure

A

Blood flow

Need contrast separates non activated vs activated tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the 3 problems of fMRIs

A

How measure neural activity in functional contrast?

How generate measurable functional contrast in experiment?

How identify functional contrast fMRI raw data?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Outline T2 contrast underlying fMRIs for problem 1 how to measure neural activity in fMRI contrast

A

Depends balance deoxygenated : oxygenated haemoglobin within blood in voxel
Then depends on local regulation arterial width
Capillaries and arteries carrying blood near inactivate neutron contain both oxygen and deoxygen haemoglobin
Near active neuroma predominantly oxygenated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Outline local neuronal activation and T2 contrast problem 1 how to measure neural activity in fMRI contrast

A

Flow increased more oxygen capillaries
Diamagnetic = not affect local magnetic field

Deoxygenated = paramagnetic field inhomogeneous. T2 signal different oxygenated and deoxygenated blood result. Different time pause

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What occurs in an inhomogeneous field during local neuronal activation in problem 1 how to measure neural activity in fMRI contrast

A

Horizontal magnetisation decays fasted (T2 decay)
Slower T2 decay increased MR signal
Blood oxygen dependent = BOLD effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Outline role of BOLD signal in problem 1 how to measure neural activity in fMRI contrast

A

Blood oxygen level dependent

Indirect measure neural activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Problem 2 how to generate functional stimulus related contrast

A

Radio frequency coil seeks excitation
Watch display on checkerboard
When stop watching and look away increase amplitude MR signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Problem 2 how to generate functional stimulus related contrast application to an experiment

A

Visual cortex max BOLD signal 6 secs after visual stimuli
Temporal delay means fMRI poor temporal resolution
24 secs per trial
2% signal change time
Peak responses only 4% higher than base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Outline spaced event related design to increase signal fMRI and address Problem 2 how to generate functional stimulus related contrast

A

Improve contrast and noise

Design types differ in temporal sequence stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Outline rapid event related design to increase signal fMRI and address Problem 2 how to generate functional stimulus related contrast

A

Stimuli e.g. category A and B
Immediately success each other with short diagnosis
Non correlated time cause it to become possible separate responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Outline block design to increase signal fMRI and address Problem 2 how to generate functional stimulus related contrast

A

All stimuli and responses external event grouped in blocks
E.g. 20 secs baseline, 20 secs rest
Increase functional contrast:noise ratio
Responses to individual events within blocks and alert stronger signal

37
Q

Outline advantages of BLOCK design

A

BOLD effect additive more stimuli = more signal
Good statistical power
Robust
Continuous activation

38
Q

Outline disadvantages of BLOCK design

A

Stimuli predictable = unsuitable many tasks
Inflexible
Limited number conditions

39
Q

How to address the problem of overlapping BOLD responses in Event related designs

A

Long stimulus intervals

Each type response unique time course - randomised ISI or randomised trial types

40
Q

Advantages of Event Related Designs

A

Avoids habituation

Analyse subtypes responses

41
Q

Disadvantages of Event Related Designs

A

Reduced sensitivity to neural events

42
Q

Aims of experimental design for fMRI

A 
Optimise contrast : noise 
Measures contrast of interest 
Baseline well controlled 
Attentional effects controlled 
Duration
43
Q

What are the spatial pre processing steps of fMRI to identify areas that show functional contrast

A

Motion correction
Co-registration between subjects fMRI and anatomical scans
Normalisation: warp scans from different individuals
Spatial smoothing

44
Q

Outline why the pre processing of motion correction to identify areas that show functional contrast has to occur

A

FMRI lasts 5-10 mins
Few subjects keep head in same position throughout
Spatial resolution 3mm movement interferes

45
Q

Outline the steps or motion correct and co registration for pre processing of fMRI

A

Motion correction;
Align each volume of brain to target volume
Detect and correct movement
Co registration BOLD results superimposed high resolution structural image

46
Q

Outline pre processing of Normalisation of fMRI

A

Subject 1 and 2 may have different head positions or different head shapes

Normalisation -> template -> average activation

47
Q

Does motion correction help with between or within or single subjects

A

Single subjects

Within subject

48
Q

Does normalisation help with between or within or single subjects

A

Between subjects

49
Q

Problem with pre processing step of normalisation

A

Belief everyone’s brain match to 1 template
Lot variability
Caveat: sulcal variability

50
Q

Outline Pre processing normalisation for comparison with anatomical template

A

Compare location in individual subjects
Example: location shows activation and has prior located in cordinal system
Get values for XYZ

51
Q

Limitations Pre processing normalisation for comparison with anatomical template

A

Only 1 brain
1 hemisphere
Fixation likely changed shape brain

52
Q

What data do you compare in block design

A

Compare signal rest with signal during blocks stimuli
Observed time course compared predicted time course = SCHEMATIC

Look voxels where predicted time course and observed time course shows good match

53
Q

Disadvantages of fMRI

A

Low power
Type 1 errors false positives

Null results impossible interpret
Do not justify region not involved
Stat maps depend on amplitude and noise

54
Q

What is phantom limb pain

A

Patient undergone amputation limb

Frequently reports sensation from lost limb

55
Q

Can myoelecteic prosthesis prevent cortical reorganisation and phantom limb pain - Lotze et al 1999

A

Injury, stimulation or training induce changes homuncular organisation primary motor cortex
Change cortical periphery brain this lost limb
Phantom limb = Perceptual correlate cortical reorganisation

56
Q

What happens when there is enhanced used of myoelectric prosthesis in phantom limbs

A

Reduced phantom limb pain

Reduced cortical reorganisation

57
Q

What is the Albert Task

A

Patient cross out all lines on sheet paper

58
Q

What are the effects of brain lesions on the Albert Task

A

Only crossed out lines to right half paper

59
Q

What is the line bisection task

A

Mark bisection point middle point of each line

60
Q

What are the effects of brain lesions on the Line Bisection Task

A

Patient chooses bisection point shifted to the right

61
Q

Outline the Drawing Task

A

Copy picture drawing
Shown image 2 flowers asked draw
From previous experiments expect ppts only draw right hand flowed

62
Q

What are the effects of brain lesions on the Drawing Task

A

In fact drew only the right hand half of BOTH flowers
Left remained blank
Flowers incomplete

63
Q

What tasks assess brain anatomy

A

Albert task

Line bisection task

Drawing task

64
Q

What is the goal of neuropsychology

A

Relate brain anatomy to behaviour
CT MRI functional localisation

Localise impaired behaviour to damaged regions - lesion May affect relay station rather originally functional region

Exclude localisation preserved skills to damaged regions. Other regions may have reorganised perform functions originally localised to damage region

65
Q

Example of neuropsychology relating brain anatomy to behaviour

A

Association: damage single brain region but multiple deficits. Syndrome

Dissociation: damage leads impaired performance in task A bit performance Task B normal

66
Q

What is an Association

A

Damage single brain region but multiple security
Require same neural circuit
Or
Separate functional regions are anatomical neighbours
Or
Area common relay station for anatomically functionally distinct regions

67
Q

Outline the example of studying Associations Balints Syndrome

A

Simultanagnosia - only perceive one item at time
Deficit of perception
Oculomotor apraxia failure make eye movements
Back and forth between 2 points
Outlining perimeter
Optic ataxia - inability reach seen target

68
Q

What Disorder is associated with studying dissociations

A

Visual form agnosia

Ventrolateral occipital lesion

69
Q

What are the two tasks to test visual form of agnosia

A

Posting task

Perceptual matching task

70
Q

Outline the posting task

A

Putting envelope through slot that can be rotated

71
Q

Outline performance in someone with visual form agnosia in posting task

A

Perform reasonably well

But not good as controls

72
Q

Outline the perceptual matching task

A

Without hand movement

Judge whether lines horizontal or vertical

73
Q

Outline performance in someone with visual form agnosia in perceptual matching task

A

Large differences between patients and controls

74
Q

Why are their apparent differences in the posting task and perceptual matching task with visual form agnosia

A

Difference between visual form to guide movements (posting task)
Vs visual form to recognise objects (perceptual matching task)

75
Q

What brain regions can account for the differences in performance with those with visual form agnosia

A

Visual form guide movements: dorsal stream
Recognise objects, orientation: ventral stream
Deteriorated visual recognition and ventral stream

76
Q

What is a dissociation study

A

Patient impaired in one task but performs normally in different task

77
Q

Why does the interference occur in dissociation task

A

Impaired task more difficult?

Performance unimpaired task at ceiling?

78
Q

Outline visual agnosia patients performance in discriminating shapes visually

A

Poor
Failed complete objects outline
Inability recognise line drawings or shapes

79
Q

Outline visual agnosia patients performance in grasping irregularly shaped objects

A

Good

80
Q

Outline optic ataxia patients performance in discriminating shapes visually

A

Good

81
Q

Outline optic ataxia patients performance in grasping irregularly shaped objects

A

Poor
Unable use visual info about object shape to control movement
Difficulty pointing or grasping movements
Symptom Balints Syndrome

82
Q

Why does Goodale et al 199 believe there are differences in optic ataxia and visual agnosia patients

A

Different brain circuits for visual perception vs visual control of skilled action

83
Q

What are the effects of visual pathway lesions to ventral stream

A

Poor visual shape discrimination

Good visually guided movement

84
Q

What are the effects of lesions to dorsal stream

A

Good visual shape discrimination

Poor visually guided movements

85
Q

Outline step 1 for measuring double dissociation for right frontal lobe lesions impairing memory for designs vs words

A

1st compare same right frontal region with controls

Right frontal lesion poorer performance memory designs

Double dissociation - compare controls right and left frontal lesions

86
Q

Double dissociation for right frontal lobe lesions impairing memory for designs vs words findings

A

Left frontal lesion worse for memory words

Non overlapping component operations
Poor memory designs due to unspecific attention deficit

87
Q

Outline limitation that variation in pathologies makes group studies difficult

A 
Inference from single patients weak 
Lesion size and location variable 
Hard find similar patients 
Normalisation scans weakens anatomical inference 
Functional anatomy variable
88
Q

Outline effects of lesion size on behavioural outcome

A

Small lesions = little effects. Robust partial damage

Small lesions strategic locations = deficit

Large lesions = damage several centres

Reorganisation: intact regions change behaviour

89
Q

How can limitations be overcome

A

Combining different methods with complementary strengths

Neuroscience (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions